Cu2ZnGeSe4 (CZGSe) and Cu2ZnGeS4 (CZGS), which contain only earth abundant elements, are promising materials for thin film solar cell devices with efficiencies of 8.4 % (CZGSe). Electronic properties of the material are triggered by intrinsic point defects. Our group showed using neutron diffraction that CZGSe adopts the kesterite type structure. For CZGS only powder X-ray diffraction data are found in literature so far, which indicate that CZGS crystallizes in the stannite type structure at room temperatures and in the wurtz-stannite type structure at high temperatures. We plan to use neutron diffraction, which is necessary to allow us the determination of the distribution of the electronical similar cations Cu+, Zn2+ and Ge4+ in the crystal structure and therefore intrinsic point defects in Cu2ZnGe(SxSe1-x)4 with x vayring from 0 to 1. This is important to gain deeper insights into the structural characteristics and to get a profound understanding of structure-property relationships.